The invention relates to a waste compacting apparatus, and relates more particularly to a waste compacting apparatus having a size reduction chamber of rectangular cross section and a compaction ram adapted for movement up to the point of size reduction.
The desirability of using size reduction chambers in waste compacting devices has long been recognized. Representative prior art devices employing this concept are shown in U.S. Pat. Nos. 3,384,007, 3,541,949, 3,802,337 and 3,815,323.
The most common arrangement, as shown in U.S. Pat. Nos. 3,384,007 and 3,802,337, employs a size reduction chamber in the shape of a truncated cone which connects a cylindrical waste receiving chamber to a cylindrical outlet snout of smaller diameter. In U.S. Pat. No. 3,541,949, a waste receiving chamber of polygonal cross section is coupled to an outlet snout of circular cross section by a transitional portion having a polygonal cross section at its inlet side and a more rounded cross section at its outlet side. In U.S. Pat. No. 3,815,323, a plurality of elongated flutes extend from the inner surface of a tubular chamber of uniform diameter to reduce the cross sectional area of a portion of the chamber.
The reduction chambers discussed above reduce chamber size either in all directions, or at least in a plurality of radial directions. These configurations require that there be no substantial protrusions around the forward peripheral portions of the compacting ram, since any such protrusion would come in contact with a portion of the size reduction chamber and prevent further forward motion of the compacting ram. This drawback has resulted in the use of a serrated shearing edge on the upper peripheral surface of the ram, as typically shown in FIG. 3 of U.S. Pat. No. 3,384,007. This type of shearing edge permits full ram travel up to the point of size reduction, which is desirable for efficient compacting, but suffers a number of drawbacks in terms of shearing efficiency and durability. The use of a serrated shearing edge also increases the likelihood of jamming, and the cutting teeth are subject to breakage. Finally, if the cutting teeth protrude even slightly from the forward edge of the ram in a system employing a prior art size reduction chamber, as shown in FIG. 2b of U.S. Pat. No. 3,802,337, the ram must necessarily stop short of the size reduction chamber to avoid interference between the protruding cutting edges and the tapering walls of the size reduction chamber, and this results in decreased compaction efficiency.